Sheriff’s deputies are searching for who’s behind the planting of an explosive device inside a port-a-potty at Oregon public park, reported KATU-TV in Portland.

Image source: KATU-TV

Image source: KATU-TV

The device was reportedly a container — such as a water or soda bottle — filled with chemicals, and it was placed inside the port-a-potty under the toilet sometime before 12:30 p.m. Saturday at Arnold Park in Aloha, Oregon.

A woman attending her daughter’s high school softball tournament was inside the port-a-potty when the explosion occurred, officials said.

“People who heard something thought it sounded like a ball had hit the port-a-potty,” RJ Puterbaugh, who was running the snack bar for the tournament, told KATU.

Image source: KATU-TV

Image source: KATU-TV

The victim was treated for a bloody head, Puterbaugh said, before paramedics rushed her to the hospital. She’s expected to be OK, KATU reported, and nobody else was hurt.

Shortly after the blast, deputies evacuated the park and searched the port-a-potties for more devices but found none. The bomb squad searched the rest of the park and surrounding area gave the all-clear a few hours later.

Image source: KATU-TV

Image source: KATU-TV

“We don’t know if the device was meant to harm somebody, or just scare folks or create a loud distraction,” Washington County Sgt. Vance Stimler told KATU.

There was a second explosion a few blocks away about 15 minutes later inside a homeowner’s mailbox, KATU noted, adding that investigators said the second explosion was caused by the same kind of device.

Stimler said whoever was responsible for the explosions could face assault charges.